Ultrakids: I haven't read this script in a while (co-wrote it with Over-the-Hill-Good-Guy when I was thirteen!), but I remember it being very simple, very basic. No flashy special effects. So in that sense, we did stick fairly close to the script just because we were forced to.
Ultrakids 2: This was a disaster. I spent a full year tossing script ideas back and forth with Over-the-Hill-Good-Guy. I read a bunch of screenwriting books, including Story by Robert McKee (which I barely understood. The only thing I got out of that book is that "nothing moves forward in the story except through conflict." Very good rule). The first draft of the movie was like 30-something pages long. Filming this movie was so hectic that I resorted to making it up as I went along, hoping that the final movie would make sense. This was a great learning experience.
Ultrakids 3: We stuck pretty closely to the script in Ultrakids 3 except for the end. The climax was completely re-written a week or two before we filmed it. I had this seven-on-one battle between the Ultrakids and Dr. Hong. No lightsabers. Dr. Hong could blast this purple magic missiles which made people disintegrate. All of the Ultrakids except Heather would've been disintegrated, then with her last ounce of strength, Heather would've turned into a lightning bolt and shot right through Dr. Hong, creating a sizzling hole in his chest (pretty graphic, right). Then all the other Ultrakids would've reappeared.
Ultrakids 4: We added a handful of scenes to this movie. Odor boy singing "Bet On It" was another last minute idea. The scene with Laserboy, Invisigirl, and Odor boy was completely ad-libbed. Halfway through production, I realized Kai had not said one word in the entire movie, so I gave him a quick dialogue scene.
The Recruits: I just re-read this script, and I'm surprised to how closely it matches the movie. I guess since there were no flashy special effects, it was easier to focus on the story. Probably the biggest change was that Laserboy was supposed to cameo at the end of the movie, but that didn't pan out.
I still think this script was really good; if we had the time to add more quality into the movie, I think it would've been really good.
Ultrakids Next Gen: We were once again forced to stick closely to the script because each scene built on top of the next. There was a billion minor changes, but for the most part, each scene was true to what was written in the script. Watching the final movie while reading the script is a very satisfying experience.